Stone

RI min

RI max

Biref min

Biref max

Dens min

Dens max

Colour

Locality

Info

nx min

nx max

ny min

ny max

nz min

nz max

Spectrum

UVS

UVL

Reference

Herderite

1.58

1.611

0.029

0.031

3.04

3.04

green

Minas Gerais, Brazil

1.58

1.58

1.61

1.61

580nm or 585nm line

faint to weak, yellow, yellowish green, blue, greenish blue, violet

inert to weak blue, green-blue, violet

Gems & Gemology 2004 spring, p61

Herderite

1.58

1.606

0.026

0.026

3.04

3.04

yellowish green

lijn 585nm

faint yellowish green

inert

Gems & Gemology 1996 fall, p 208

Herderite

1.58

1.61

0.03

0.03

3.05

3.05

greenish yellow

Virgem da Lapa, Minas Gerais, Brazil

6.13ct, biaxial -

weak purple

moderate purple

GIA Gem Database  34282

Herderite

1.58

1.608

0.028

0.028

3.04

3.04

yellowish green

Brazil

17.16ct, biaxial -

weak violet

moderate violet

GIA Gem Database  35365

Herderite

1.581

1.61

0.029

0.029

3.02

3.02

light green

Brazil

biaxial-, 5.90ct

1.581

1.581

1.601

1.601

1.610

1.610

violet

pale violet

The Journal of Gemmology 1977 N°1, p27-28

Herderite

1.583

1.62

0.037

0.037

3.02

3.02

red purple

Brazil

7.12ct, biaxial -

inert

inert

GIA Gem Database  35408

Herderite

1.585

1.61

0.025

0.025

3

3

violet

Brazil

2.40ct

no features

inert

inert

GIA Gem Database  35421

Herderite

1.586

1.616

0.029

0.03

3.02

3.04

light green

Pakistan

weak 585nm line

violet

 blue

Gems & Gemology 2006 summer, p174-175

Herderite

1.59

1.62

0.03

0.03

3.04

3.04

light red-purple

Virgem da Lapa, Minas Gerais, Brazil

4.93ct, biaxial -

inert

inert

GIA Gem Database  34283

Hydroxylherderite

1.59

1.62

0.03

0.03

3.02

3.02

purple

1.57ct

no features

inert

inert

The Journal of Gemmology 2019 36 (6), p 501-503

Stone

RI min

RI max

Biref min

Biref max

Dens min

Dens max

nx min

 nx max

ny min

ny max

nz min

nz max

Reference

Herderite

1.555

1.617

0.028

0.034

2.94

3.05

Gemmo.eu 2017

Herderite

1.556

1.62

0.029

0.03

2.95

3.02

1.556

1.590

1.578

1.610

1.589

1.620

Michael O'Donoghue, Gems: Their Sources, Descriptions and Identification (2006),  873pp 

Herderite

1.58

1.627

0.023

0.032

2.9

3.04

1.580

1.604

1.601

1.613

1.611

1.627

Tables of Gemstone Identification, Roger Dedeyne, Ivo Quintens, 2007 

Herderite

1.581

1.624

0.029

0.03

2.95

3.02

http://www.gemmology.be 

Herderite

1.581

1.642

0.029

0.032

3

3

1.581

1.610

1.601

1.613

1.610

1.642

Gems, R Webster, 5th edition 1994 

Herderite

1.585

1.627

0.024

0.034

2.95

3.02

1.585

1.605

1.619

1.627

Gemme, Dati per l'identificazione, P. De Stefano et al, 1993 

Herderite

1.587

1.645

0.023

0.032

2.9

3

1.587

1.604

1.619

1.645

Bestimmungstabellen für Edelsteine, Birgit Günther, 2008 

Herderite

1.587

1.642

0.032

0.032

2.9

3.02

1.587

1.610

1.609

1.630

1.619

1.642

Gemmological Tables, Ulrich Henn, 2004 

Herderite

1.591

1.624

0.029

0.03

2.95

3.02

1.581

1.594

1.601

1.613

1.610

1.624

Joel Arem, Color Encyclopedia of Gemstones, 1987 

Herderite

1.591

1.621

0.028

0.028

3

3

John Sinkakas, Gemstone and mineral data book,1972 

Herderite

1.591

1.624

0.029

0.03

2.95

3.02

1.591

1.594

1.611

1.613

1.619

1.624

http://www.geminterest.com 

Herderite

1.594

1.624

0.03

0.03

3

3

Tabellen zur Edelstein-Bestimmung, Pschichholz FGA, 1975 

STONE

LOCALITIES

REFERENCE

Herderite

Minas Gerais

Brazil

Joel Arem, Color Encyclopedia of Gemstones, 1987